Duct-piercing machine



Aug. 13, 1963 J. J. vARGA DUCT-PIERCING MACHINE 4 Sheets-Sheet 1 Filed July 29, 1959 Ffa. Z.

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Aug. 13, 1963 .1.J. vARGA DUCT-PIERCING MACHINE 4 Sheets-Sheet 3 Filed July 29, 1959 Aug 13, 1963 J. J. VARGA 3,100,413

DUCT-PIERCING MACHINE Filed July 29, 1959 4 sheets-sheet 4 f/Wea/f (jaseyb d Valga f MM @dalla- /4//3 AVM/wg! ilnited be tes anemia DUCT-PERCHNG MACHlNE Joseph J'. Varga, Fairieid, Conn., assigner to General Electr-ie Company, a corporation of New York Filed July 29, 1959, Ser. No. 830,336 4 Claims. (Cl. Sli-181i) This invention relates to a duct-piercing machine or press adapted for punching sections out of a duct under circumstances in which a die cannot be xedly positioned with respect to its associated punch.

In a conventional punch press, a die composed of very hard material is iixedly positioned and a punch of similar hard material is disposed to make reciprocal movement toward and away from mating engagement with the die. A panel of sheet material positioned between the die and punch will then have a section the shape of the die sheared out upon the stroke of the punch toward the die.

Where the material to be pierced or punched is in the form of a duct, a ysingle aperture can be punched therein only by means of a special press and then only near the ends thereof.

Where it has been desired to position a number of apertures along a length of duct, it has heretofore been necessary to utilize boring or drilling processes. These are quite expensive-particularly in cases where other-thanround apertures are desired.

One of the objects of the presen-t invention is to provide a machine or press which can pierce or punch apertures along the entire length of a long section of duct or tubing.

Another object of .the invention is to provide a machine or press having a die which can be positioned well within the interior of a section of duct or tubing.

Another object of the invention is to provide a machine o1 press in which punch and die alignment is provided by utilizing a work piece as a reference point.

Other objects of the invention will become apparent from the following specification considered in conjunction with the attached drawings in which FIG. 1 is a broken sectional view illustrating the principal elements of this invention.

FIG.' 2 is a broken sectional perspective illustrating one end of the duct mounting arm, punch, die, and duct centering means of this invention.

FIG. 3 is a broken plan view tof the die centering means of this invention. K

FIG. 4 is a View taken along the lines 4--4 Vof FIG;` 3.

FIG. 5 is a partial section-al view taken along the lines 5--5 of FIG. 2.

IFIG. 6 is a broken perspective view of an alternative duct centering mechanism of the invention.

FIG. 7 is a broken sectional view illustrating the operation of the mechanism of FIG. 6.

FIG. 8 is a schematic view illustrating the control circuit of the machine of this invention.

Briefly sta-ted, in accordance with one of its embodiments, the invention is directed to a duct piercing machine comprising a base, an elongated duct-mounting arm pivotally fastened to the base at one end thereof, the opposite end of the arm being movable, a die positioned on the movable end of the arm, a punch disposed for mating engagement with the die, means for positioning a duct mounted around the arm with respect to the punch, and means for positioning the die with respect to the duct whereby the die is in mating engagement with the punch.

The machine of this invention comprises a base ltl on lbdil Patented Aug. 13, 1%63 ice which is mountedV a reciprocating punch mechanism 11 which may be of the conventional type wherein a punch element 12 is brought toward the base with great force. Instead of the usual stationary die element engageable by the punch element 12, there is a movable die 13)` positioned near the end lof a duct mounting arm 14 which is not fastened at the end on which the die 13 is mounted but is fastened to the base 1d `by means of a pivot 15 here shown as a bolt, at the other end. Thetree or unanchored end of the duct mounting arm 14 has a tapered head 16 in order Ito make it easy to thread duct into position on the arm 14. As best shown in FIG. 2, the free end of the duct mounting arm 14 has restricted movement comprising a narrowl arc around the pivot 15. The only necessary movement is that necessary to enable a section of duct or tubing to be mounted on the mounting arm 14.

Positioned on the mounting arm 14 near the die 13 is l a die-positioning assembly 17 best shown in FIGS. 3

and 4. The assembly 17 comprises links 1S, 19, Ztl, land 21 anchored to the mounting arm 14 by spaced-fixed pivots 22 and 23 and connected in tandem to each other by means of intermediate pivots 24 and 25 and a central pivot-26 positioned within a longitudinal slot 27 in which the pivot 26 has -a longitudinal movement. Also positioned in the slot 27 is a rod 28 connected to the pivot 26, the rod 28 serving to anchor a draw line 29 held taut by means of 1a biasing spring 30'. The links 18, 19, Zt, and 21 are symmetrically disposed upon the mounting arm 14 so that the pivots 24 and 25 extend outward the same distance from thev central pivot 26. When the draw line 2i? is subjected to pulling action, the symmetry of the assembly 17 is maintained but the linkage angles are changed as the pivot 25 moves along the longitudinal axis of the mounting arm 14. This movement causes the pivots 24 and 25L to move away from each other and v when a section of duct is mounted on Ithe mounting arm 14 the pivots 24 and 25 will make contact with the interior sides of the duct and thus position the die 13 with respect to the duct.

In order to make the die-positioning assembly operable by electrical control, the draw line 29v is attached to the draw arm 31 of an air cylinder 32 mounted upon the base 10. The air cylinder 32 has its operation controlled by means of a solenoid valve las shown schematically in FIG. 8.

Mounted upon the base 1dr near the `tree end of the mounting arm 14 is a duct-positioning assembly 3?;` which is best illustrated in FIG. 5. Fixedly positioned upon the base 1t) are a pair of bearing posts 34 on which there is mounted a clamp 35-having reciprocal movement toward and away from the base lil. The clamp 35 is biased to a position away from the base 10 by means of biasing springs 36. The clamp 35 is -forced toward the base 10 by a rocker arm 37 mounted on a Vfulcrum 38 by means of a pivot 39. The rocker arm 37 is actuated by the draw arm 4t? of an air cylinder 41 which is in turn controlled by a solenoid valve as best shown in schematic form in FIG. 8. In FIG. 5, the clamp 35 is shown positioning a duct 42, the mounting arm being omitted from FIG. 5 in order to illustrate the ductpositioning assembly more clearly. As best shown in yFIG. l, a plurality of rollers 43 are mounted on the base 1) immediately under the duct mounting arm 14 in order to reduce the effort required in positioning a duct around the mounting arm 14.

FIGS. 6 and 7 illustrate an alternative duct-positioning assembly. .In FIG. the clamp 35 positions the duct 42 by exerting pressure against the corners thereof. It

has been found that certain sections of duct have one of the corners rounded more than the other with the result that the duct does not assume the desired position. 'In order to correct for the non-uniformity of'duct sec- V tions, the assembly of FIGS. -6V and'7, which is a preferred form, comprises a pair of bearing posts 44 having mounted Vfor reciprocal movement thereon a member 45 (shown displaced from the-'bearingy vpostsV for the sake of clarity) having apair of end` posts 46 extending therefrom. The end posts 46 terminate at Vtheir extremities in angled surfaces which'serve as cams to drive a pair of slider clamps 47 mounted on Yclamp bases' 4S. The member 45 is reciprocated by means of an arm 49 controlled by an air cylinder (not shown) similar to the .air cylinderV 41. The slider clamps 47 are biased toV an open position by means of four coil springs Sii. `The slider clamps 47 are equipped with inclinedfsurfaces which complement the extending surfaces of the posts 46 whereby the reciprocal motion imparted to the member4 45 is translated through a 90 angle to the slider 'clamps 47. As best shown in FIG. 7, a work piece 52 is gripped from the sides by the slider clamps 47 and thus alack ofuniformity in the corners of'a duct will-not preventv the duct from being properly oriented with respect to the punch 12. Y

From the above, it may be seen that the alignment of a punch and die is achieved by aligning a work piece with respect to a punch and a die with respect to the work vpieceactions which may take place simultaneously. Since uniformity of wall thickness of ducts is -not achieved inractual practice, it is desirable that a greater-than-normal clearance be maintained between the punch and die. Thus, where clearance of the order oftor 5 thousandths .of an inch is suiiicient in the case of a'die and punch where the positions of both are fixed, it is desirablev in practicing the present invention Vto allow a clearance of about 12 thousandths of an inch between the punch and Vdie;v Obviously, the punch and die clearance must be related to the dimensional tolerance of the duct or tubing constituting the wor-k pieces. Ithas been lfound, however, that clearance of l2 thousandths of an inch' is suiiicient for the metal ducts conventionally used in wiring commercial buildings. The length of duct which can be 'piercedV is 4limited'onl'y by the length of the duct mounting arm 14. Machines are readily designed to accommodate ducts of a length of ten feet or more. l

FIG. 8 is a schematicdiagrarn of the control circuit Aof this invention. The circuit is shown with operating and interlock switches in the open Vposition as they would be prior to the mountingof a duct upon the duct mounting arm 14. Power to operate the air cylinders 32 and 41 is provided by y.compressed air entering a solenoid valve 60 through an air intake tube 61. The solenoid valve 60 is double acting, having an operate portion tla and a release or restoreV portion 6%. The air cylinders 32 and 41 are likewise double operating so that restoration to a non-operated position requires the positive application of air. Inasmuch as both of the cylinders 32 and 41 act at the same time, they may be controlled by a single electrically actuated solenoid valve 60. Movement of the punch .12 is controlled by a circuit through a punch control solenoid `62.

In operating the machine of this invention, a section of duct is threaded onto the duct mounting arm 14, an action which closes an interlock switch 63 which prevents operationof the press unless a section of duct is mounted on the arm 14. A manual switch 64 has double-throw contacts which are normally in the position illustrated to operate a release circuit through release portion 60h of the solenoid -valve 60. When it is desired to begin a punch cycle, the manual switch 64 is depressed to kcomplete a circuit from a supply lead 65 through Yconductors 67 and 63, the operate portion 66a of solenoid valve 60, and supply lead 66 whereupon the air cylinders 32 and 41 actuate the die-positioning and duct-positioning devices respectively. Operation of these devices closes interlockY switches I69 and 7) to prepare the operating circuit for the press 11. The interlock'switches 69 and 70 insure that the press 11 will not be operated until the die 13 is positioned in alignment with the punch element 12.

As a safety precaution to insure that the operator will not have one hand idle during openation of the press 11,

f the switch 64 is included in the interlock circuit for operation of the press 11. As soon as the duct and die positioning devices have operated, the operator closes a second manual switch 71 which is spaced a suflicient distance -Srorn the switch 64 so that the operator will depress the switch '64 with his righthand and the switch 71 with his left hand. This completes the `press operating circuit from lead 65 :through switch G4, interlock switch 63, interlock switch 70', interlock switch 69, manual switchV 71, solenoid 62, and lead 66. The press 11 now stants its operating cycle and in so doing trips an interlock switch 72 which closes a hold circuit through the operate portion 60a of solenoid switch 6i). :T he purpose of this circuit is to insure that the duct and die positioning devices will Vrein-ain in operated position in the event the operator releases the switch 64. .Once started, .the press 11 operates in the conventional manner to complete a cycle where- Y upon it returns to the position indicated in FIG. 8 with the interlock switch 72 in open position. The operator then releases switches 64 and 71, the switch 64 thereby opening the operate circuit 6Go through the solenoid lvalve and closing the release circuit Gilb. This restores the air cylinders 32 and 41 to their linitial -unoperated position and ope-ns the interlock switches 69 and 70. The work piece may now be positioned for a new punch operation or may fbe removed from the mounting arm 14.

The interlock switches 63, 69, 79, and 72 are of a type which are cont/rolled by the movement of a mechanical element. These switches may be of the type known in the trade as microswitches While the invention has beendescribed with reference to certain specific embodiments thereof, it is obviousvthat there may be many variations -which jwill fall the ftrue vspirit of the invention. Therefore, the invention should not vbe limi-ted except as may be necessitated by the scope of the appended claims. L

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A `duct-piercing machine comprising a base, a punch mounted on said base, said punch having reciprocating movement with respect to saidr base, an elongated ductmounting arm having a movable end positioned lbetween said base and said punch and an anchored end extending away from said punch, a die positioned to make mating engagement with said punch mounted on the movable end of said arm, a clamp mounted on said base, a portion of said clamp havin'greciprocal Vmovement parallel to the reciprocal movement of said punch, said portion being spring biased to a release position and having beveled nndersurfaces lspaced with respect tol said punch for making `contact `with a duetto center asection of duct with respect to said punch, and a die-positioning device mounted on saidarmnear said die, said die-positioning device being adapted to tit inside a duct and having controllable expansion elements adapted Vto engage the sides ofY the interior surface of a duct to position said die with respect to said duct and align said die with said punch.

2. A duct-piercing machine as claimed in claim l wherein the die-positioning device is spring biased to a release position and is actuated by means of adraw l-iue extending to the anchored end of the arm on which said device is mounted. k

`3. A `duet-piercing machine as claimed in claim 2. wherein the die-positioning-device consistsV of tour links connected in tandem Iby means of two lintermediate pivots and a Ieentral pivot, said links ybeing symmetrically mounted on the arm by means of two spaced iixed pivots at the extreme ends of said links, 'the intenmediate pivots being movable 'with a lchange in linkage angles and the central pivot having restricted movement in a direction parallel `fto the longitudinal direction of said arm.

4. A duct-piercing machine as claimed in claim 3 Wherein the draw line is 1connected to :the ventral pivot whereby draw action forces the intermediate pivots to expand outward into contact with the interior of a duct.

UNITED STATES PATENTS Lothropi Dec. 25, 1883 Olmsted Apr. 30, 1889 Hawkins May 7, 1929 Copple Sept. 29, 19311 Turner May l5, 1934 4 Adams et a1. 1 Olot. 28,k 1952 Brehm Feb; 1U, 1953 

1. A DUCT-PIERCING MACHINE COMPRISING A BASE, A PUNCH MOUNTED ON SAID BASE, SAID PUNCH HAVING RECIPROCATING MOVEMENT WITH RESPECT TO SAID BASE, AN ELONGATED DUCTMOUNTING ARM HAVING A MOVABLE END POSITIONED BETWEEN SAID BASE AND SAID PUNCH AND AN ANCHORED END EXTENDING AWAY FROM SAID PUNCH, A DIE POSITIONED TO MAKE MATING ENGAGEMENT WITH SAID PUNCH MOUNTED ON THE MOVABLE END OF SAID ARM, A CLAMP MOUNTED ON SAID BASE, A PORTION OF SAID CLAMP HAVING RECIPROCAL MOVEMENT PARALLEL TO THE RECIPROCAL MOVEMENT OF SAID PUNCH, SAID PORTION BEING SPRING BIASED TO A RELEASE POSITION AND HAVING BEVELED UNDERSURFACES SPACED WITH RESPECT TO SAID PUNCH 